Semiaromatic polyamides are excellent in low water absorption property as well as in heat resistance and mechanical properties, and are used in a lot of electric and electronic components and in peripheral components of engines in vehicles. The semiaromatic polyamides used in the electric and electronic components, among these components, are required to have further higher degree of flame retardancy.
As a method for imparting flame retardancy to resins, methods using flame retardants are usually adopted. Recently, from the growing environmental awareness, halogen-based flame retardants have been avoided, and in general, nonhalogen-based flame retardants have been used.
For example, Patent Literature 1 and Patent Literature 2 disclose the use of the mixtures, as nonhalogen-based flame retardants, each composed of the reaction product between melamine and phosphoric acid, a phosphinic acid salt and a metal compound, and any of these mixtures is disclosed to satisfy the flame retardancy standard, the UL94 V-0 standard, in a 1/16-inch molded product.
However, a resin composition including a polyamide and a phosphinic acid salt is significant in metal corrosion. Accordingly, such a composition intensively abrades, during melt processing, the metal components such as the screw and the die of an extruder, and the screw and the die of a molding machine, and hence is disadvantageously poor in mass productivity. Such a composition also disadvantageously generates a large amount of gas during molding processing the composition and causes attachment of contamination to the die.
With respect to these problems, the present inventors have disclosed, in Patent Literature 3, a technique to suppress the metal corrosion and the generation of gas by using boehmite as a stabilizer in the resin composition including a polyamide and a phosphinic acid salt.